It will not work with Uverse in the sense that you won't need AT&T's box to go with it. You can't plug this device into a phone jack and expect it to deliver Uverse service. This is only for DSL be it from AT&T or otherwise.
I'm not sure what you mean by extend. Do you mean use it in conjunction with another wireless router? Or perhaps you mean get the wireless access point to be seen further away? Or do you mean to use it as a seperate router from the same location?
A Netgear wireless router can handle up to 32 clients and a dual band can then handle 64 clients. This is a N300 ADSL2+ DualBand router and can handle up to 64 clients.
